Today,
as we steal from the old "Perry Mason" TV
show, we are going to discuss the "Case of the
Tired Ferret." (Yes, I know I am dating myself with
that reference.)

Sneaky
(great name for a ferret!) is a 3-year-old ferret who
recently has been spending more time than usual
sleeping. He does have moments of activity and still
seems to be eating well but his naps have grown longer
and longer and his play time is correspondingly greatly
reduced. Ferrets do spend quite a bit of time sleeping;
however, their awake time is virtually nonstop. Wild
ferrets use this nonstop awake time hunting, while
captive ferrets spend this awake time getting into
mischief. Sneaky is definitely having a problem.

Sneaky’s
apparent lack of energy could reflect any number of
potential disease processes and we do not have the room
to discuss all of them. In fact, I probably cannot even
think of all of them, but I can share with you the most
common possible cause for Sneaky’s symptoms.

Ferrets
have a propensity to develop a disease called insulinoma.
This disease occurs when one or more tumors (insulinomas)
develop in a ferret’s pancreas. These tumors produce
insulin in excess of what is needed for normal blood
sugar maintenance and this excess insulin causes a
reduction in blood sugar directly proportional to the
amount of excess insulin.

Insulin,
as I mentioned, is produced by the pancreas and is used
in the body to bring sugar (glucose) from the blood
steam into the cells of the body to be used as an energy
source. It is a beautifully balanced system designed to
maintain an appropriate blood sugar level while
providing the body’s cells with the fuel they need to
work. When insulin levels rise unchecked, as is the case
with insulinoma, the blood sugar level drops. This will
cause weakness and excessive sleeping initially as
demonstrated by Sneaky, but as the process progresses,
the blood sugar can drop so low as to cause seizures.
This is the body’s attempt to "shake loose"
stored glucose from the muscles as they spasmodically
contract during a seizure in order to fuel the body.
Further progression of the condition results ultimately
in death.

Insulinoma
in ferrets can occur as one or a few nodular masses
within the pancreas or many often-microscopic masses
throughout the pancreas. Diagnosis is relatively simple,
requiring a blood sample to measure, among other things,
blood sugar level and insulin level. If the insulin
level is too high relative to the blood sugar level, we
have a diagnosis of insulinoma. We do not, however, know
which form we are dealing with. Personally, I like to
use ultrasound imaging of the pancreas in a ferret with
insulinoma to try to determine if there are but one or a
few nodules within. If that is the case, a relatively
straightforward surgical procedure can be performed to
remove the nodules.

If
it is more likely that there are many tiny nodules
throughout the pancreas, there are a couple of options
for treatment. One is a surgical procedure to remove a
large portion of the pancreas, thus eliminating a
significant number of the tiny insulinomas and hopefully
resolving the excess insulin production as a result.
This can be very successful, but there are cases that
even with removal of 90 percent of the pancreas, insulin
levels remain too high. These cases require medical
therapy to counteract the excess insulin. Unfortunately,
this therapy is not curative and is therefore lifelong.
It does, however, usually afford control of the disease
allowing the ferret to live a more normal active life.